1. Field of the Invention
The present invention relates to a process of sanitizing water in swimming pools, spas, and hot tubs wherein the level of bacteria is lowered. In particular, the present invention relates to a process of sanitizing by treating said water with a bactericidal effective amount of a combination of di-isodecyl dimethyl ammonium chloride and copper (II) ions and also treating said water at least intermittently with an oxidant selected from the group consisting of available chlorine, available bromine and ozone.
2. Brief Description of the Prior Art
Water in swimming pools, spas and hot tubs is constantly recirculated and fresh water is normally added only to maintain the desired volume. Although this water is usually filtered continuously to keep it free of suspended matter, it frequently contains bacteria. Treatment with one or more sanitizers to control the bacteria count is necessary.
Numerous chemical compounds have been reported for use in swimming pools, spas, and hot tubs. These chemicals include various quaternary ammonium salts, copper salts, and oxidants such as chlorine sources or bromine sources or ozone or peroxy compounds such as hydrogen peroxide and potassium peroxymonosulfate (OXONE). The use of combinations of such sanitizers is also known.
At the present time, the main disinfectant used in swimming pools, spas and hot tubs is chlorine. It is an effective bactericide, but suffers from two main disadvantages. One, at improper pH and concentration levels it may cause eye irritation. Two, it has to be added at frequent intervals to maintain an effective concentration for killing bacteria.
Ozone has also been used as a disinfectant for swimming pools, spas and hot tubs; but, it is limited to frequent or continuous dosing to maintain an effective concentration for killing bacteria. Such frequent or continuous treatments are required with ozone since there is at the present time no technology available for providing residual ozone. Also, if people come into contact with high concentrations of ozone, such as where the ozone is injected into the water, they may experience unpleasant headaches and the like.
Certain quaternary ammonium compounds have also been reported as being useful in swimming pools, spas, and hot tubs as bacteristats, bactericides, and algaecides. Those used as bacteristats and bactericides have required relatively high levels (e.g. over 100 ppm by weight) to give the rapid bacteria kill times needed for pool treatment. However, at such high concentration levels, quaternary ammonium salts in general have the potential of producing objectionable, aesthetically unpleasing turbid swimming pool water having a high total organic carbon (TOC) content. Furthermore, such high concentrations of quaternary ammonium salts may increase the likelihood of skin irritation of people using those bathing facilities.
Quaternary ammonium salts have also been used in swimming pools, spas and hot tubs as algaecides. For example, known commercial algaecide products include SUN.RTM. Algae Preventor (an alkyl dimethyl benzylammonium chloride) and HTH.RTM. Non-Foaming Algaecide Concentrate [poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylene dichloride]]. Such algaecides are used in relatively low concentrations (under 10 ppm by weight). At such concentrations, these known quaternary ammonium algaecides generally do not provide the rapid kill times for swimming pools.
In practice, harmful bacteria must be killed rapidly if they are present in a swimming pool, spa or hot tub. Indeed, the standard test method for disinfectants in swimming pools [American Organization of Analytical Chemists (A.O.A.C.) test method 4.047 entitled "Disinfectants (Water) for Swimming Pools"] requires that a swimming pool bactericide kills high levels of bacteria in only 30 seconds of contact. With quaternary ammonium salts, this rapid bactericidal activity must be accomplished at low concentrations, e.g. 60 ppm or less, to avoid the potential of producing objectional, unpleasing turbid swimming pool water having a high total organic carbon (TOC) content as well as increasing the likelihood of skin irritation of people using these bathing facilities.
It is believed that the present invention represents a viable alternative to the above-noted problems with existing swimming pool, spa and hot tub bactericides.
Examples of references describing the use of individual quaternary ammonium compounds or other water-treatment bactericides or combinations of bactericides for water treatment and other applications include:
U.S. Pat. No. 3,510,424, which issued to Zumbrunn on May 5, 1970, teaches that inorganic and organic peroxoacids such as peroxosulfuric acid and its salts and peroxodisulfuric acid and its salts may be used to convert toxic cyanides in industrial effluent streams to nontoxic and hydrolysable cyanates.
U.S. Pat. No. 3,567,729, which issued to Lewis et al. on Mar. 2, 1971, teaches the use of certain quaternary ammonium salts as germicides.
U.S. Pat. No. 3,624,082, which issued to Lewis et al. on Nov. 30, 1971, teaches a process for making selected quaternary ammonium salts which may be useful as germicides.
U.S. Pat. No. 3,702,298, which issued to Zsoidos et al. on Nov. 7, 1972, teaches a method of treating swimming pools with a combination of a peroxy salt, such as salts of peroxymonosulfuric acid, and a copper salt.
U.S. Pat. No. 3,730,702, which issued to Shay et al. on May 1, 1973, teaches a method of inhibiting microorganisms by applying thereto selected water-soluble unsymmetrical di-higher alkyl dimethyl ammonium salts. This product may be used to disinfect hard surfaces, fabrics, topical portions of the body and water.
U.S. Pat. No. 3,733,420, which issued to Wakeman et al. on May 18, 1973, teaches a method of inhibiting microorganisms in hard water aqueous solutions [e.g., swimming pools (see col. 3, line 15)] using octyl dodecyl dimethyl ammonium salts. It is noted that this invention is stated to be useful for bactericidal purposes (see col. 4, line 11).
U.S. Pat. No. 3,845,216, which issued to Brink et al. on Oct. 29, 1974, teaches a method of controlling the growth of bacteria in aqueous systems by contacting the system with a combination of B-bromo-B-nitrostyrene and didecyldimethyl ammonium chloride.
U.S. Pat. No. 4,098,602, which issued to Seymour et al. on Jul. 4, 1978, teaches an algicidal composition comprising selected ammonium quaternary compounds and a copper complex formed by reacting a water insoluble copper compound and alkanol amines.
U.S. Pat. No. 4,311,598, which issued to Verachtert on Jan. 19, 1982, describes a process for the disinfection of a bacteria-containing aqueous medium by contacting that medium with a combination of hydrogen peroxide or peroxyacid, a soluble copper salt and an autoxidisable reducing agent (e.g., 1,2,3-trihydroxybenzene, benzaldehyde, dihydroxyfumaric acid, malonic acid, ascorbic acid, or an alkali metal sulfate.
U.S. Pat. No. 4,450,174, which issued to Green et al. on May 22, 1984, describes the use of di-n-decyl dimethyl quaternary ammonium salts to inhibit bacteria in aqueous systems.
U.S. Pat. No. 4,594,091, which issued to Givan on Jun. 10, 1986, is directed to the use of certain boron derivatives to inhibit algal and fungal growth in water.
U.S. Pat. No. 4,790,940, which issued to Costaldi et al. on Dec. 13, 1988, teaches a process for the treatment of free cyanide-containing wastewater to destroy the free cyanide content thereof by treating said waters under alkaline conditions with polysulfide in the presence of a cationic surfactant catalyst (e.g., dialkyldimethyl quaternary ammonium salt).
U.S. Pat. No. 4,923,619, which issued to Legros on May 8, 1990, teaches the treatment of water of swimming pools and industrial water by means of a combination of (a) quaternary ammonium salts and (b) water-soluble copper and/or silver salts and peroxide compounds releasing oxygen, such as monopersulfate or peroxidisulfate of potassium. See col. 1 of this patent.
U.S. Pat. No. 4,952,398, which issued to Tapin on Aug. 28, 1990, teaches the treatment of swimming pool water using the combination of a quaternary ammonium compound and a copper salt as a biocide.
U.S. Pat. No. 5,131,938, which issued to Girvan on Jul. 21, 1992, suggests that certain boron derivatives may be used for killing algae and fungus in swimming pools. This patent further teaches that these boron derivatives may be used with known pool sanitizers (e.g., halogens, copper, hydrogen oxide, ozone, oxone, and quaternary ammonium compounds). See col. 5 of this patent.
U.S. Pat. No. 5,149,354, which issued to Delaney on Sep. 22, 1992, suggests a composition to inhibit the growth of algae, fungi, and bacteria, and to prevent the formation of turbidity in pool water comprising certain amounts of (a) copper sulfate, (b) silver nitrate, (c) sodium gluconate, (d) zinc chloride or zinc sulfate, (e) water, and (f) a complexone capable of forming water-soluble copper complexes (e.g., EDTA or a suitable alkali metal salt thereof).
United Kingdom Pat. Application 2,194,227, filed by Crystalclear S. A. and published on Mar. 2, 1988, teaches treating a body of water, such as a swimming pool, by adding thereto a liquid component and an oxidizing component. The liquid component comprises a polymeric cationic quaternary ammonium compound, a sequestering agent, and a copper salt. The oxidizing component may include sodium perborate, potassium persulfate, an alkali or alkaline earth hypochlorite, a trichloroisocyanurate, or an alkali metal dichloroisocyanurate.
European Pat. No. 59,978, which was granted to Bayrol on Jun. 13, 1984, claims a process for the disinfection of water and the oxidative decomposition of oxidizable impurities contained in the water by adding to the water the combination of (a) quaternary ammonium compounds, (b) water-soluble copper salts and or silver salts, and (c) an oxygen-liberating peroxide compound (e.g., potassium hydrogen monopersulfate).
European Pat. Application No. 0286453, which was filed by Pernox Manufacturing Company and published on Oct. 12, 1988, describes a biocidal composition for the treatment of water comprising certain quaternary ammonium compounds together with copper cations and/or a biocide containing a gem. halonitromethylene group.
G. R. Bhat et al. "The Green Hair Problem: A Preliminary Investigation", J. Soc. Cosmet. Chem. Vol. 30, 1-8 (January/February 1979) suggests that the combination of copper and peroxide enhances the phenomenon of blond hair acquiring a green tint. The experiments in this paper included a test where the blond hair was oxidized with hydrogen peroxide and immersed in a commercial formulation of a quaternary ammonium compound (distearyl dimethyl ammonium chloride).
L. K. Landeen et al. "Efficacy of Copper and Silver Ions and Reduced Levels of Free Chlorine in Inactivation of Legionella Pneumophila", Applied and Environmental Microbiology, Dec. 1989 pages 3045-3050, describes the activity of copper and silver ions in the presence of low levels of free chlorine against Legionella pneumophila.
M. T. Yahya "Disinfection of Bacteria in Water Systems by using Electrolytically Generated Copper:Silver and Reduced Levels of Free chlorine", Con. J. Microbiol. Vol. 36, pages 109-116, 1990, describes the activity of copper or silver ions with low levels of free chlorine against various bacteria in water.
G. P. Fitzgerald "Compatibility of Swimming Pool Algicides and Bactericides, Water & Sewage Works," vol. 115(2), pages 65-71 (1968), teaches that various amines, quaternary ammonium compounds, copper and silver salts have algistatic, algicidal, and bactericidal properties in swimming pools.
U.S. EPA Freedom of Information Request RIN-5973-92 shows that Bio-Guard MSA Algicide made by Bio-Lab, Inc. of Decatur, Ga. in 1974 contained the combination of copper and a quaternary ammonium compound (dimethyl dichlorobenzyl ammonium chloride).
Separately, di-isodecyl dimethyl ammonium chloride (sold commercially as BTC-99, by Stepan Co.) has been reported as having several uses.
Stepan Product Bulletin for BTC-99 (copyright 1990) states BTC-99 is useful as a microbiocide for swimming pool and cooling water treatment applications. A typical maintenance dose for a swimming pool is 3 oz. per 20,000 gallons. This brochure states that BTC-99 has demonstrated complete destruction of various algae including Green Algae, Square D Algae, Blue-Green Algae, and Black Algae.